At age 16, James T. McCain worked to register voters in Sumter in 1921. He continued his civil rights activity while he served as the southeastern region field secretary for Congress of Racial Equality (CORE). He was responsible for more than 30 Freedom Schools and over 70,000 black and white volunteers.
McCain served as the founding president of the Sumter County branch of the NAACP. He helped to organize protest marches in Greenville to end segregation at the airport. He assisted the black and white Freedom Riders, who tested the interstate commerce laws, with bail when they were arrested. McCain helped Blacks register to vote and was one of the background organizers for the 1963 March on Washington.